Methods of making mercaptan compounds using nickel-molybdenum catalysts

Abstract

Methods for synthesizing a mercaptan compound include the steps of contacting a nickel-molybdenum catalyst with H2S at a sulfiding temperature of less than or equal to 235° C. to form a supported sulfur-containing catalyst, and then contacting an alcohol compound or an olefin compound, H2S, and the supported sulfur-containing catalyst to form a reaction mixture containing the mercaptan compound.

We claim: 
     
       1. A process for producing a mercaptan compound, the process comprising:
 (i) contacting a nickel-molybdenum catalyst with inlet H 2 S at an inlet sulfiding temperature from about 10° C. to about 90° C. and sulfiding the nickel-molybdenum catalyst with H 2 S at a sulfiding temperature of less than or equal to about 235° C. to form a supported sulfur-containing catalyst; and 
 (ii) contacting an alcohol compound or an olefin compound, H 2 S, and the supported sulfur-containing catalyst to form a reaction mixture comprising the mercaptan compound. 
 
     
     
       2. The process of  claim 1 , wherein:
 the alcohol compound, H 2 S, and the supported sulfur-containing catalyst are contacted in step (ii); 
 the mercaptan compound has formula (A): R 1 —SH; 
 the alcohol compound has formula (B): R 1 —OH; and 
 R 1  is a C 1  to C 18  substituted or unsubstituted, cycloalkyl group or linear or branched alkyl group. 
 
     
     
       3. The process of  claim 1 , wherein:
 the olefin compound, H 2 S, and the supported sulfur-containing catalyst are contacted in step (ii); 
 the mercaptan compound has formula (C): R 2 —SH; 
 the olefin compound has the formula H 2 C═CH 2  or formula (D): R 1 —CH═CH 2 ; 
 R 1  is a C 1  to C 18  substituted or unsubstituted, cycloalkyl group or linear or branched alkyl group; and 
 R 2  is a C 3  to C 20  substituted or unsubstituted, cycloalkyl group or linear or branched alkyl group. 
 
     
     
       4. The process of  claim 1 , wherein:
 the alcohol compound comprises methanol, ethanol, a propanol, a butanol, a pentanol, a hexanol, a heptanol, an octanol, a nonanol, a decanol, an undecanol, a dodecanol, a tridecanol, a tetradecanol, a pentadecanol, a hexadecanol, a heptadecanol, an octadecanol, cyclopentanol, cyclohexanol, or any combination thereof; and 
 the olefin compound comprises ethylene, propylene, a butene, a pentene, a hexene, a heptene, an octene, a decene, a dodecene, a tetradecene, a hexadecene, an octadecene, cyclopentene, cyclohexene, or any combination thereof. 
 
     
     
       5. The process of  claim 1 , wherein the mercaptan compound is methyl mercaptan, ethyl mercaptan, isopropyl mercaptan, or sec-butyl mercaptan. 
     
     
       6. The process of  claim 1 , wherein step (i) is conducted at:
 a sulfiding temperature from about 60° C. to about 200° C.; and 
 a sulfiding pressure from about 50 to about 250 psig. 
 
     
     
       7. The process of  claim 1 , wherein the inlet sulfiding temperature is from about 20° C. to about 80° C. 
     
     
       8. The process of  claim 1 , wherein step (ii) is conducted at:
 a temperature in a range from about 100° C. to about 300° C.; 
 a pressure in a range from about 50 to about 1000 psig; and 
 a WHSV in a range from about 0.01 to about 3. 
 
     
     
       9. The process of  claim 1 , wherein step (ii) comprises contacting the alcohol compound or the olefin compound and H 2 S with a fixed bed of the supported sulfur-containing catalyst. 
     
     
       10. The process of  claim 1 , wherein a molar ratio of H 2 S:alcohol compound or H 2 S:olefin compound is in a range from about 3:1 to about 30:1. 
     
     
       11. The process of  claim 1 , further comprising, prior to step (i), a step of contacting the nickel-molybdenum catalyst with an inert gas at a purging temperature of less than or equal to about 235° C. 
     
     
       12. The process of  claim 11 , wherein:
 the inert gas comprises nitrogen; and 
 the purging temperature is from about 60° C. to about 200° C. 
 
     
     
       13. The process of  claim 1 , wherein:
 a yield to the mercaptan compound is at least about 50 mol %; and/or 
 a conversion of the alcohol compound or the olefin compound is at least about 50 mol %. 
 
     
     
       14. The process of  claim 1 , wherein the reaction mixture contains less than or equal to about 10 mol % of non-mercaptan reaction products. 
     
     
       15. The process of  claim 1 , wherein a selectivity of the mercaptan compound is at least about 80 mol %, based on the total mercaptan compounds in the reaction mixture. 
     
     
       16. The process of  claim 1 , further comprising a step of isolating the mercaptan compound from the reaction mixture to form a product stream containing the mercaptan compound. 
     
     
       17. The process of  claim 1 , wherein unreacted alcohol compound or unreacted olefin compound is recycled after step (ii). 
     
     
       18. The process of  claim 1 , wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst independently comprise:
 a solid support; 
 from about 1 to about 5 wt. % nickel; and 
 from about 4 to about 18 wt. % molybdenum. 
 
     
     
       19. The process of  claim 18 , wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst independently contain less than or equal to about 3 wt. % carbon. 
     
     
       20. The process of  claim 18 , wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst independently are characterized by a BET surface area from about 100 to about 300 m 2 /g. 
     
     
       21. The process of  claim 18 , wherein the supported sulfur-containing catalyst contains from about 3 to about 18 wt. % sulfur. 
     
     
       22. The process of  claim 18 , wherein the solid support comprises silica, alumina, magnesia, boria, titania, zirconia, a zeolite, a mixed oxide thereof, or a mixture thereof.